System for simulating the condyle movements

Abstract

A system for simulating the condyle movements, for use in forming dental protheses, comprises a sensing apparatus including structures engageable with the cranium and mandible arch, and a reproducing apparatus which repeats the mastication movements sensed by sensing apparatus. The mastication movements are sensed by inductive sensors mounted on the sensing apparatus.

What is claimed is: 
     
       1. A system for simulating the condyle movements, comprising a sensing apparatus and a reproducing apparatus which imposes the mastication movements on two arch moulds as determined by the sensing apparatus, wherein: said sensing apparatus comprises a structure for fitting to the cranium and thereby to the maxillary arch, a structure engageable with the mandible arch, means for generating a signal representing the relative distance between points of the two structures and the front of the arches, at a distance from the condyles, and two induction means each disposed adjacent to a respective one of the two condyles, each said induction means comprising a group of three flat mutually perpendicular reference electrodes mounted on one of the structures, and a ball mounted on the other structure and cooperating with the electrodes in such a manner that a set of three relative positioning signals is generated by induction between the ball and the individual electrodes during the free movements; and   said reproducing apparatus comprises two structures movable relative to each other, a base supporting one of said structures, and three extendable articulated members supporting the other of said structures, two of said members each having an end displaceable in two directions under the control of two of the signals of the two sets of three signals, the third signal controlling the extension of said members.   
     
     
       2. A system as claimed in claim 1, wherein the reproducing apparatus further comprises disc means supported by the two structures for carrying the moulds, and the sensing apparatus further comprises bracket means arranged to engage the two structures of the sensing apparatus, and means for forming the two moulds of the patient, said moulds being placed on the respective discs of the two structures of the reproducing apparatus in a spacial position corresponding to that of the arches in the sensing apparatus, and said bracket means being removed before the two apparatuses begin to move. 
     
     
       3. A system as claimed in claim 1, wherein in the sensing apparatus, the structure for fitting to the cranium comprises two slides, a double-threaded bar for moving said slides, arms carried by the slides, and ear pieces, said ear pieces and said groups of three electrodes being carried by said arms, and the structure engageable with the mandible arch comprising two articulated arms having ends at which the balls are mounted, said arms being displaceable symmetrically, means defining a seat in one of said electrodes, and gauging means including a shank for fitting into said seat and means defining a recess for the respective ball, for defining a zero position. 
     
     
       4. A system as claimed in claim 1 wherein, in the sensing apparatus, the structure for fitting to the cranium rests on the glabella, and is engaged with a temporary prothesis on the maxillary arch. 
     
     
       5. A system as claimed in claim 1, wherein, in the reproducing apparatus, one of said structures is a lower structure, and the other of said structures is an upper structure, and the lower one of the two structures comprises two slides which can be adjusted in position to correspond to the position of the two balls, first and second servo-mechanisms linked to the slides, each of said servo-mechanisms being controlled by one of said signals which represents the vertical condyle displacement signal, two further servo-mechanisms controlled by the other two signals for displacing said first and second servo-mechanisms, and a third servo-mechanism coupled to the front of the two structures and operative to set the relative spacing at the front of the apparatus. 
     
     
       6. A system as claimed in claim 5, wherein the reproducing apparatus further comprises two balls carried by the said slides of the lower structure, two additional slides each carrying a group of three flat electrodes which are adjustable to correspond to the position of the electrodes of the sensing apparatus, each said group cooperating with one of said balls, and means for correcting the orientation of the electrodes, in order to introduce corrections to the masticatory movements.